Reactor loop nuclide on-line monitoring system and method

Abstract

The invention discloses a reactor loop nuclide on-line monitoring system and method, relates to the technical field of reactors, and can solve the technical problem that whether a fuel element cladding is damaged or not cannot be accurately monitored on line at present. The system comprises a sampling module, a control module and a monitoring module, the sampling module comprises a main loop and a target loop which are connected in parallel; the control module is used for controlling a loop coolant to flow in the main loop and the target loop so as to stop the loop coolant in the target loop as a loop coolant to be detected, and the loop coolant in the main loop keeps flowing; and the monitoring module is used for monitoring the activity of target gamma radionuclide in the loop coolant to be detected.

Description

Technical Field

[0001] This invention relates to the field of reactor technology, and in particular to an online monitoring system and method for nuclides in reactor loops. Background Technology

[0002] As the core component of the reactor, if the fuel element is damaged, fission products will enter the primary circuit, which can seriously affect the operation and radiation safety of the reactor. Therefore, it is necessary to monitor the internal condition of the fuel element online, such as whether the fuel element cladding is damaged.

[0003] Currently, existing monitoring methods include periodic manual sampling and analysis and online total gamma monitoring. Periodic manual sampling involves manually sampling the loop coolant periodically into a container and then conducting offline monitoring in a laboratory. However, this method suffers from several drawbacks: first, it has a long sample pretreatment time; second, it cannot monitor fuel element cladding damage online, resulting in a monitoring lag; and third, the sampling personnel receive a high radiation dose. While online total gamma monitoring is online, it measures the loop coolant flowing in the main loop. Because the flowing coolant is not a fixed sample and the time span is long, the final monitoring results are easily affected by local inhomogeneities. Both periodic manual sampling and analysis and online total gamma monitoring are conducted before reactor shutdown. In addition to these two methods, there is also offline siphoning, which involves removing fuel elements from the reactor after shutdown and placing them in a container for testing. This method cannot reflect fuel element cladding damage online. Therefore, there is an urgent need for an online method to monitor fuel element cladding damage. Summary of the Invention

[0004] In view of this, the present invention provides an online monitoring system and method for nuclides in reactor loops, which can solve the technical problem that it is currently impossible to accurately monitor whether the fuel element cladding is damaged online.

[0005] According to a first aspect of the present invention, an online monitoring system for nuclides in a reactor loop is provided, the system comprising: Preferably, the monitoring module includes a shielding unit, a detection unit, a collimation unit, and a data processing unit; The shielding unit includes a shielding chamber, the shielding chamber includes a receiving cavity and a collimation hole communicating with the receiving cavity, the detection unit includes a detector, the detector is located in the receiving cavity, and the probe of the detector is opposite to the collimation hole, the collimation hole is used to be opposite to the target circuit, so that the probe receives γ-rays emitted by the coolant of the circuit under test in the target circuit; The shielding chamber also includes shielding components covering both sides of the collimation hole. The collimation unit is used to adjust the distance between the shielding components to adjust the collimation width of the collimation hole to the target collimation width. The detector is used to detect γ-rays in the coolant of the circuit under test that pass through the target circuit and the collimation hole in sequence and enter the probe, thereby obtaining a first energy spectrum signal. The data processing unit is used to determine the activity of the target γ-radionite in the coolant of the circuit to be tested based on the first energy spectrum signal, the known γ-radionite activity of the radioactive standard solution, and the target standard width.

[0006] Preferably, the sampling module includes one main circuit and N pipelines; The control module is also used to control one of the N pipelines to move to be opposite to the collimation hole, and to use the pipeline that moves to be opposite to the collimation hole as the target loop, wherein N is greater than or equal to 1, so as to detect loop coolant from different sources or loop coolant from the same source at different times.

[0007] Preferably, the sampling module further includes: an N+1th pipeline, wherein the N+1th pipeline contains a radioactive standard solution; The control module is also used to control the N+1th pipeline to move to be opposite to the collimation hole; The collimation unit is also used to adjust the collimation width of the collimation aperture so that the intensity of the γ rays in the radioactive standard solution entering the detector through the N+1th pipeline and the collimation aperture in sequence meets the dead time requirement, thereby obtaining the target collimation width range. The collimation unit is also used to adjust the collimation width of the collimation hole to different target standard widths within the range of the target standard width; The detector is also used to detect γ rays in the radioactive standard solution that enter the probe sequentially through the N+1th pipeline and the collimation hole under different target standard widths, and to obtain a second energy spectrum signal corresponding to each target standard width; The data processing unit is further configured to calculate the efficiency value corresponding to the target standard width based on the known γ radionuclide activity of the radioactive standard solution, the second energy spectrum signal, and the target standard width corresponding to the second energy spectrum signal, and to determine the target γ radionuclide activity in the coolant of the circuit under test based on the first energy spectrum signal, the efficiency value corresponding to the target standard width, and the target standard width.

[0008] Preferably, the N+1th pipeline includes: a section to be tested and a non-tested connection section. The section to be tested is a rigid pipe so that the distance from each position of the coolant in the target circuit emitting gamma rays to the detector corresponds to the distance from each position of the radioactive standard solution emitting gamma rays to the detector in the N+1th pipeline. This makes the efficiency value corresponding to the target collimation width determined based on the known gamma radionuclide activity of the radioactive standard solution used to calculate the target gamma radionuclide activity in the coolant of the target circuit. The non-tested connection section is a flexible pipe to enable the movement of the pipeline.

[0009] Preferably, the data processing unit is configured to calculate the absolute activity by multiplying the first energy spectrum signal by the efficiency value corresponding to the target standard width, calculate the target cross-sectional area with the target standard width as the diameter, calculate the volume of the coolant in the test circuit by multiplying the target cross-sectional area by the length of the test segment, and calculate the target γ radionuclide activity of the coolant in the test circuit by the ratio of the absolute activity to the volume.

[0010] Preferably, the system further includes: an alarm module; The alarm module is used to determine whether the casing is damaged based on the activity of the target gamma radionuclide. If it is damaged, an alarm signal is issued.

[0011] Preferably, the detection unit further includes a cooler located in the receiving cavity, used to adjust the operating temperature of the detector to a preset temperature range.

[0012] According to a second aspect of the present invention, a method for online monitoring of nuclides in a reactor loop is provided, the method comprising: The control loop coolant flows in the main loop and the target loop to cut off the loop coolant in the target loop as the coolant for the loop under test, while the loop coolant in the main loop remains in flow, wherein the target loop and the main loop are connected in parallel; Monitor the activity of the target γ-radioactive nuclide in the coolant of the circuit under test.

[0013] Preferably, the monitoring of the activity of the target γ radionuclide in the coolant of the circuit under test includes: Adjust the collimation width of the collimation hole to the target collimation width; The first energy spectrum signal is obtained by detecting the γ-rays in the coolant of the circuit under test that pass through the target circuit and the collimation hole in sequence and enter the probe. The activity of the target γ-radionium nuclide in the coolant of the circuit under test is determined based on the first energy spectrum signal, the known γ-radionium activity of the radioactive standard solution, and the target standard width.

[0014] By employing the above technical solution, this invention provides an online monitoring system and method for nuclides in the reactor loop. On the one hand, the function of the loop coolant is to circulate, passing through the reactor core and absorbing the heat released during nuclear fuel fission to prevent fuel damage due to overheating. Therefore, the loop coolant cannot be static. On the other hand, since the flowing loop coolant is not a fixed sample and spans a long period, the final monitoring results are easily affected by local inhomogeneities. Therefore, accurate detection requires the loop coolant to be static. Thus, current accurate detection cannot be performed online and requires offline detection, i.e., the loop coolant must be removed and taken to a laboratory for detection. However, the technical solution of this invention sets up a parallel bypass, i.e., a target loop, in the main loop. The loop coolant flows in both the main loop and the target loop. When detection is needed, the loop coolant in the target loop is stopped, while the main loop continues to flow. This ensures that the detected loop coolant is static, while also ensuring that there is always flowing loop coolant, thereby achieving accurate online monitoring of whether the fuel element cladding is damaged and reducing the radiation risk to personnel from offline sampling.

[0015] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This diagram illustrates the structure of an online monitoring system for nuclides in a reactor loop provided by an embodiment of the present invention. Figure 2 This invention provides a schematic diagram of another reactor loop nuclide online monitoring system according to an embodiment of the present invention. Figure 3 This diagram illustrates a structural schematic of a shielding unit and a target circuit according to an embodiment of the present invention. Figure 4 This diagram illustrates a structural schematic of a main circuit and a target circuit according to an embodiment of the present invention. Figure 5 This diagram illustrates a structural schematic of a main circuit and a target circuit with valves according to an embodiment of the present invention. Figure 6 This diagram illustrates a multi-pipeline structure according to an embodiment of the present invention. Figure 7A schematic flowchart of an online monitoring method for nuclides in a reactor loop provided by an embodiment of the present invention is shown; Figure 8 A schematic diagram of an online monitoring device for nuclides in a reactor loop provided by an embodiment of the present invention is shown. Detailed Implementation

[0017] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0018] This embodiment provides an online monitoring system for nuclides in a reactor loop, such as... Figure 1 As shown, the system includes: a sampling module, a control module, and a monitoring module; the sampling module includes a main loop and a target loop connected in parallel; the control module is used to control the flow of loop coolant in the main loop and the target loop, so as to stop the loop coolant in the target loop as the loop coolant to be tested, while the loop coolant in the main loop continues to flow; the monitoring module is used to monitor the activity of the target γ radionuclide in the loop coolant to be tested.

[0019] It should be noted that, on the one hand, the function of the loop coolant is to circulate through the reactor core, absorbing the heat released during nuclear fuel fission and preventing the fuel from being damaged by overheating. Therefore, the loop coolant cannot be stationary. On the other hand, since the flowing loop coolant is not a fixed sample and spans a long period of time, the final monitoring results are easily affected by local inhomogeneities. Therefore, accurate detection requires the loop coolant to be stationary. Thus, current accurate detection cannot be performed online and must be done offline, that is, the loop coolant must be removed and taken to the laboratory for detection.

[0020] In this embodiment, a parallel bypass, namely the target circuit, is set up in the main circuit. The loop coolant flows in both the main circuit and the target circuit. When detection is required, the loop coolant in the target circuit is stopped (since the target circuit is set up based on the detection needs, the loop coolant in the target circuit is stopped as the detection sample), while the main circuit continues to flow. This ensures that the detected loop coolant is stationary (ensuring the accuracy of the detection) and that the loop coolant is always flowing (ensuring the cooling effect).

[0021] In order to ensure that the coolant in the target circuit is fully replaced and a representative sample is obtained, the coolant can be allowed to flow entirely from the target circuit without flowing from the main circuit. After it is determined that the coolant in the target circuit is fully replaced (for example, if the duration of the coolant flowing entirely from the target circuit without flowing from the main circuit is longer than a preset duration, it is determined that the coolant is fully replaced), before the coolant in the target circuit is stopped, the coolant is allowed to flow in both the main circuit and the target circuit.

[0022] Specifically, such as Figure 4 The diagram shows the structure of the main loop and the target loop. The straight line represents the main loop, and the curved line represents the target loop. (The connection points between the main loop and the target loop are open, meaning the coolant reaching the two connection points splits into two paths: one flows into the main loop, and the other flows into the target loop. Both ends of the main loop are connected to the reactor core, circulating continuously.) To achieve the interception of the coolant in the target loop, one implementation method is as follows: Figure 5 As shown, valve 3 is installed on the main circuit, and valves 1 and 2 are installed on the target circuit. The control module controls valve 3 to close, valve 1 to open, and valve 2 to open, so that all the coolant in the circuit flows through the target circuit instead of the main circuit. The control module controls valve 3 to open, valve 1 to close, and valve 2 to close, so that the coolant in the circuit flows through the main circuit. The coolant in the target circuit that is blocked between valves 1 and 2 is used as the coolant for the circuit under test. Preferably, valves 1, 2, and 3 are all solenoid valves. A manual valve is also installed on the target circuit as a safety measure to prevent the circuit from failing to stop due to a malfunction of valves 1 and 2.

[0023] The control module includes a programmable logic controller (PLC), a digital-to-analog converter (DAC), a photoelectric multiplier, cables, and control analysis software. The cables include power cables and data transmission cables. Data transmission cables can be fiber optic. Signal transmission has independent transmission capabilities via fiber optic cables and network cables, minimizing signal loss through signal noise reduction and signal multiplication techniques. The control analysis software controls the entire system operation, including setting detector parameters and controlling detector operation, such as starting and ending detection, solenoid valve switching control, and collimation parameter setting and adjustment. The software can batch process previously collected historical energy spectrum signals even when the system is offline. It can perform independent energy spectrum analysis without relying on the spectral analysis program provided with the digital spectrometer and is compatible with multiple operating systems. The control analysis unit includes remote hardware such as computers and mobile terminals. The data processing unit is used for data analysis and processing, including energy spectrum signal collection, nuclide activity calculation, trend graph presentation, and database management. The database stores previously collected historical energy spectrum signals, efficiency values ​​corresponding to the standard width of each target, energy spectrum diagrams, etc., and can be queried by time. The activity of the target gamma radionuclide in the coolant of the circuit under test can be displayed in the form of an energy spectrum.

[0024] Furthermore, the activity trend of the target gamma radionuclide in the coolant of the test loop can be analyzed over time, for example, by selecting a time period of 24 hours, one week, or three months, without limitation. Based on the change curve data of the target gamma radionuclide activity in the coolant of the test loop within the selected time period, on the one hand, the change curve data can be displayed visually as a graph in the display window of the output screen, so that the risk of potential fuel element cladding failure can be predicted in a timely manner based on the change trend, and it is also beneficial to carry out source term analysis of the coolant in the high-temperature and high-pressure irradiation test loop. On the other hand, the activity of the target gamma radionuclide at each data point and the activity of the target gamma radionuclide displayed in the form of an energy spectrum can be viewed in real time in the display window of the output screen.

[0025] Preferred, such as Figure 2 and Figure 3As shown, the monitoring module includes a shielding unit, a detection unit, a collimation unit, and a data processing unit. The shielding unit includes a shielding chamber, which includes a receiving cavity and a collimation hole communicating with the receiving cavity. The detection unit includes a detector located in the receiving cavity, with the detector's probe facing the collimation hole. The collimation hole is used to face the target circuit so that the probe receives gamma rays emitted by the coolant of the circuit under test in the target circuit. The shielding chamber also includes shielding components covering both sides of the collimation hole. The collimation unit is used to adjust the distance between the shielding components to adjust the collimation width of the collimation hole to the target collimation width. The detector is used to detect gamma rays in the coolant of the circuit under test that pass through the target circuit and the collimation hole sequentially and enter the probe, obtaining a first energy spectrum signal. The data processing unit is used to determine the activity of the target gamma radionuclide in the coolant of the circuit under test based on the first energy spectrum signal, the known gamma radionuclide activity of the radioactive standard solution, and the target collimation width.

[0026] In this embodiment, since only gamma rays passing through the collimation aperture can be detected by the detector, while gamma rays that cannot pass through the collimation aperture are shielded, the collimation width of the collimation aperture determines the amount of gamma rays entering the detector. The shielding component, acting as the top cover of the receiving cavity, can, in one implementation, move left and right to shorten the distance between the two shielding components, thus reducing the collimation width of the collimation aperture; conversely, it can widen the distance between the two shielding components, thus increasing the collimation width of the collimation aperture. This can be achieved by the control module sending commands to the collimation unit, which then executes them. For example, the control module sends a command to the collimation unit to narrow the collimation width. Upon receiving this command, the collimation unit shortens the distance between the two shielding components, thereby achieving automatic adjustment of the collimation width and reducing the workload, low efficiency, and error-prone nature of manual adjustments.

[0027] To prevent or reduce the impact of ambient radiation on detection accuracy, the shielding unit is made of high-density and easily processed materials, such as iron, lead, or tungsten alloys, with a shielding thickness of 5-10 cm. Figure 3 As shown, the lower opening of the receiving cavity is used to install and place the detector inside the receiving cavity from below.

[0028] Preferably, the sampling module includes one main loop and N pipelines; the control module is further used to control one of the N pipelines to move to be opposite to the collimation hole, and the pipeline that moves to be opposite to the collimation hole is used as the target loop, wherein N is greater than or equal to 1, so as to detect loop coolant from different sources or loop coolant from the same source at different times.

[0029] In this embodiment, since there is only one detector, only one path can be measured at a time. As one implementation method, because coolant from different sources is in the same pipeline, interference will occur between them, reducing detection accuracy. Therefore, to meet the detection requirements of coolant from different sources, multiple pipelines need to be set up. As another implementation method, to meet the requirement of detecting coolant from the same source but at different times, multiple pipelines need to be set up, placing coolant from different times in different pipelines to achieve the requirement of time-delay measurement. Figure 6 As shown, each valve 1 is connected to a pipeline via a pipe. There are multiple pipelines; the diagram only shows four as an example, without limitation. The material, wall thickness, and other specifications of all pipelines are consistent. The detector can be a high-purity germanium P-type detector. The detector's probe receives gamma rays emitted by the coolant in the circuit under test. The detector's digital spectrometer then converts the gamma rays into a raw signal, such as a pulse signal. This raw signal is amplified, shaped, and then converted from analog to digital. The converted digital signal is then processed to obtain the first energy spectrum signal.

[0030] In this method, one of the N pipelines is moved to be opposite the collimating aperture, so that the gamma rays emitted by the loop coolant in the other pipelines towards the detector are shielded within the effective detection area, thus enabling detection of the loop coolant only in that specific pipeline (target loop). Figure 3 As shown, the electric motor provides the power to move the pipeline to the position opposite the collimation orifice.

[0031] Preferably, the sampling module further includes: an (N+1)th pipeline containing a radioactive standard solution; the control module is further configured to control the (N+1)th pipeline to move relative to the collimation aperture; the collimation unit is further configured to adjust the collimation width of the collimation aperture so that the intensity of the gamma rays in the radioactive standard solution entering the detector sequentially through the (N+1)th pipeline and the collimation aperture meets the dead time requirement, thereby obtaining a target standard width range; the collimation unit is further configured to adjust the collimation width of the collimation aperture to different target standard widths within the target standard width range; the detector is further configured to... Under different target standard widths, gamma rays in the radioactive standard solution that sequentially enter the probe through the N+1th pipeline and the collimation hole are detected to obtain a second energy spectrum signal corresponding to each target standard width. The data processing unit is also used to calculate the efficiency value corresponding to the target standard width based on the known gamma radionuclide activity of the radioactive standard solution, the second energy spectrum signal, and the target standard width corresponding to the second energy spectrum signal, and to determine the target gamma radionuclide activity in the coolant of the test circuit based on the first energy spectrum signal, the efficiency value corresponding to the target standard width, and the target standard width.

[0032] Preferably, the data processing unit is configured to calculate the absolute activity by multiplying the first energy spectrum signal by the efficiency value corresponding to the target standard width, calculate the target cross-sectional area with the target standard width as the diameter, calculate the volume of the coolant in the test circuit by multiplying the target cross-sectional area by the length of the test segment, and calculate the target γ radionuclide activity of the coolant in the test circuit by the ratio of the absolute activity to the volume.

[0033] In this embodiment, if too many gamma rays enter the detector through the collimation aperture, the detector will become stuck, leading to inaccurate detection. If too few gamma rays enter the detector through the collimation aperture, the detector will accumulate fewer gamma rays, resulting in a large statistical error and inaccurate detection. Therefore, the dead time parameter reflects whether there are too many or too few gamma rays. Thus, by adjusting the collimation width of the collimation aperture, the intensity of gamma rays entering the detector is made to meet the dead time requirement, corresponding to the target collimation width range. That is, any target collimation width within this range will ensure that the intensity of gamma rays entering the detector meets the dead time requirement.

[0034] The gamma radionuclide activity of the radioactive standard solution is known and can be used to calculate the target gamma radionuclide activity in the coolant of the test loop. The specific calculation process involves calculating the efficiency value corresponding to different target standard widths based on the gamma radionuclide activity of the radioactive standard solution, and then calculating the target gamma radionuclide activity in the coolant of the test loop based on the efficiency value corresponding to different target standard widths.

[0035] The radioactive standard solution is detected, and a second energy spectrum signal corresponding to a target standard width is obtained. The second energy spectrum signal is the number of second signals detected per unit time. Multiplying this by the target efficiency value (unknown here) corresponding to the target standard width, the standard absolute activity is obtained. Dividing the standard absolute activity by the volume of the radioactive standard solution (the N+1th pipeline is a cylinder, and the volume of the radioactive standard solution = the length of the section to be tested multiplied by the cross-sectional area with the target standard width as the diameter) yields the known gamma radionuclide activity of the radioactive standard solution. Thus, the target efficiency value corresponding to the target standard width can be obtained. Similarly, the target efficiency values ​​corresponding to all target standard widths can be obtained.

[0036] Then, in application, the coolant of the test loop is detected to obtain the first energy spectrum signal corresponding to the standard width of the target. This signal is multiplied by the target efficiency value (which is known here) corresponding to the standard width of the target to obtain the absolute activity. The absolute activity is then divided by the volume of the coolant of the test loop (the target loop is a cylinder, and the volume of the coolant of the test loop = the length of the test section multiplied by the cross-sectional area of ​​the target with the standard width of the target as the diameter) to obtain the activity of the target γ radionuclide in the coolant of the test loop, thus achieving precise quantification.

[0037] Preferably, the N+1th pipeline includes: a section to be tested and a non-tested connection section. The section to be tested is a rigid pipe so that the distance from each position of the coolant in the target circuit emitting gamma rays to the detector corresponds to the distance from each position of the radioactive standard solution emitting gamma rays to the detector in the N+1th pipeline. This makes the efficiency value corresponding to the target collimation width determined based on the known gamma radionuclide activity of the radioactive standard solution used to calculate the target gamma radionuclide activity in the coolant of the target circuit. The non-tested connection section is a flexible pipe to enable the movement of the pipeline.

[0038] For this embodiment, as Figure 6 As shown, between valve 1 and valve 2, there is a non-test section that is inflexible (rigid pipe) and a non-test section that is flexible (soft hose). It should be noted that the flexible non-test section can be either valve 1 or valve 2, and it is not required that the flexible non-test section must be connected to valve 1.

[0039] Based on the key monitoring index values ​​of the hardware equipment, the key technical parameters of the hardware equipment are monitored in real time to monitor the working status of the hardware equipment. The working status of the hardware equipment includes: the status of valve 1, valve 2, valve 3, the working status of the detector, and the working status of the collimation unit. Preferably, such as Figure 2 As shown, the system also includes: a device status display module. The device status display module is also used to receive the working status signal from the detector, the working status signal from the solenoid valve of the sampling module, and the working status signal from the collimation unit. If there is an abnormality, it will give a fault or damage warning information. For example, when there is an abnormality, the device icon will be displayed in red and a warning will be given in text form, which will facilitate the maintenance and troubleshooting of the device.

[0040] Preferred, such as Figure 2 As shown, the system also includes an alarm module; the alarm module is used to determine whether the casing is damaged based on the activity of the target γ radionuclide, and if damaged, to issue a damage alarm signal.

[0041] Preferred, such as Figure 2 As shown, the detection unit further includes a cooler located in the receiving cavity, used to adjust the operating temperature of the detector to a preset temperature range. The cooler is either electrically refrigerated or undergoes condensation refrigeration.

[0042] Preferably, the system further includes a temperature and humidity control module; the temperature and humidity control module is used to meet the working temperature and humidity requirements within the cabinet, wherein the sampling module, the collimation unit, the detection unit, and the control module are integrated within the cabinet. The temperature and humidity control module includes an industrial air conditioner and a temperature and humidity sensor, which can control the temperature to meet the environmental conditions detected by the online monitoring device. For example, the temperature is controlled at greater than or equal to 5°C and less than or equal to 25°C. When the system also includes a cooler and a shielding unit, the cooler and shielding unit are also integrated within the cabinet. The data processing unit and alarm module, as terminals, are not integrated within the cabinet. The operating status of the hardware also includes the temperature and humidity within the cabinet. The equipment status display module is also used to receive operating status signals from the temperature and humidity control module. If an abnormality is detected, a fault or damage warning message is given. For example, in case of an abnormality, the equipment icon is displayed in red, and a text warning is given to facilitate equipment maintenance and troubleshooting.

[0043] This invention provides an online monitoring system and method for nuclides in the reactor loop. On one hand, the function of the loop coolant is to circulate through the reactor core, absorbing the heat released during nuclear fuel fission and preventing fuel damage due to overheating. Therefore, the loop coolant cannot be static. On the other hand, since the flowing loop coolant is not a fixed sample and the time span is long, the final monitoring results are easily affected by local inhomogeneities. Therefore, accurate detection requires the loop coolant to be static. Thus, current accurate detection cannot be done online and requires offline methods, i.e., the loop coolant must be removed and taken to a laboratory for detection. However, the technical solution of this invention sets up a parallel bypass, i.e., a target loop, in the main loop. The loop coolant flows in both the main loop and the target loop. When detection is needed, the loop coolant in the target loop is stopped, while the main loop continues to flow. This ensures that the detected loop coolant is static, while also ensuring that there is always flowing loop coolant, thereby achieving accurate online monitoring of whether the fuel element cladding is damaged and reducing the radiation risk to personnel from offline sampling.

[0044] Furthermore, a method for online monitoring of nuclides in the reactor loop is provided, such as... Figure 7 As shown, the method includes: 101. The control loop coolant flows in the main loop and the target loop to cut off the loop coolant in the target loop as the coolant for the test loop, while the loop coolant in the main loop continues to flow, wherein the target loop and the main loop are connected in parallel.

[0045] 102. Monitor the activity of the target γ radionuclide in the coolant of the circuit under test.

[0046] For steps 101-102 of the embodiment, the monitoring of the activity of the target γ-radioactive nuclide in the coolant of the test circuit includes: adjusting the collimation width of the collimation aperture to the collimation width of the target; detecting γ-rays in the coolant of the test circuit that pass through the target circuit and the collimation aperture sequentially and enter the probe to obtain a first energy spectrum signal; and determining the activity of the target γ-radioactive nuclide in the coolant of the test circuit based on the first energy spectrum signal, the known activity of the γ-radioactive nuclide in the radioactive standard solution, and the collimation width of the target.

[0047] First, the radioactive standard solution is detected, and a second energy spectrum signal corresponding to a target standard width is obtained. The second energy spectrum signal is the number of second signals detected per unit time. Multiplying this by the target efficiency value (unknown here) corresponding to the target standard width, the standard absolute activity is obtained. Dividing the standard absolute activity by the volume of the radioactive standard solution (the N+1th pipeline is a cylinder, and the volume of the radioactive standard solution = the length of the section to be tested multiplied by the cross-sectional area with the target standard width as the diameter) yields the known gamma radionuclide activity of the radioactive standard solution. Thus, the target efficiency value corresponding to the target standard width can be obtained. Similarly, the target efficiency values ​​corresponding to all target standard widths are obtained.

[0048] Then, in application, the coolant of the test loop is detected to obtain the first energy spectrum signal corresponding to the standard width of the target. This signal is multiplied by the target efficiency value (which is known here) corresponding to the standard width of the target to obtain the absolute activity. The absolute activity is then divided by the volume of the coolant of the test loop (the target loop is a cylinder, and the volume of the coolant of the test loop = the length of the test section multiplied by the cross-sectional area of ​​the target with the standard width of the target as the diameter) to obtain the activity of the target γ radionuclide in the coolant of the test loop, thus achieving precise quantification.

[0049] Furthermore, as Figure 7 The specific implementation of the method shown in this invention provides an online monitoring device for nuclides in a reactor loop, such as... Figure 8 As shown, the device includes: a control module 21 and a monitoring module 22; Control module 21 is used to control the flow of loop coolant in the main circuit and the target circuit, so as to cut off the loop coolant in the target circuit as the coolant of the circuit under test, while the loop coolant in the main circuit continues to flow, wherein the target circuit and the main circuit are connected in parallel; Monitoring module 22 is used to monitor the activity of the target γ radionuclide in the coolant of the circuit under test.

[0050] In order to monitor the activity of the target gamma radionuclide in the coolant of the test circuit, the monitoring module 22 is specifically used to adjust the collimation width of the collimation aperture to the target collimation width; to detect gamma rays in the coolant of the test circuit that pass through the target circuit and the collimation aperture in sequence and enter the probe, and to obtain a first energy spectrum signal; and to determine the activity of the target gamma radionuclide in the coolant of the test circuit based on the first energy spectrum signal, the known gamma radionuclide activity of the radioactive standard solution, and the target collimation width.

[0051] It should be noted that other corresponding descriptions of the functional units involved in the reactor loop nuclide online monitoring device provided in this embodiment can be found in [reference needed]. Figure 7 The corresponding description will not be repeated here.

[0052] Based on the above, Figure 7 Accordingly, this embodiment also provides a storage medium, which may be volatile or non-volatile, storing a computer program that, when executed by a processor, implements the above-described method. Figure 7 The method for online monitoring of nuclides in the reactor loop is shown.

[0053] Based on this understanding, the technical solution of the present invention can be embodied in the form of a software product, which can be stored in a storage medium (such as a CD-ROM, USB flash drive, portable hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods of various implementation scenarios of the present invention.

[0054] Based on the above, Figure 7 The method shown and Figure 8 To achieve the above objectives, this embodiment also provides a computer device, which includes a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to implement the above-described... Figure 7 The method for online monitoring of nuclides in the reactor loop is shown.

[0055] Optionally, the computer device may also include a user interface, a network interface, a camera, radio frequency (RF) circuitry, sensors, audio circuitry, a Wi-Fi module, etc. The user interface may include a display screen, input units such as a keyboard, etc., and optional user interfaces may also include USB interfaces, card reader interfaces, etc. The network interface may optionally include standard wired interfaces, wireless interfaces (such as Wi-Fi interfaces), etc.

[0056] Those skilled in the art will understand that the computer device structure provided in this embodiment does not constitute a limitation on the physical device, and may include more or fewer components, or combine certain components, or have different component arrangements.

[0057] The storage medium may also include an operating network communication module. An operating system is a program that manages the hardware and software resources of the aforementioned computer device, supporting the operation of information processing programs and other software and / or programs. The network communication module is used for communication with various components within the storage medium, as well as with other hardware and software within the information processing entity.

[0058] Through the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platform, or it can be implemented by hardware.

[0059] This invention provides an online monitoring system and method for nuclides in the reactor loop. On one hand, the function of the loop coolant is to circulate through the reactor core, absorbing the heat released during nuclear fuel fission and preventing fuel damage due to overheating. Therefore, the loop coolant cannot be static. On the other hand, since the flowing loop coolant is not a fixed sample and the time span is long, the final monitoring results are easily affected by local inhomogeneities. Therefore, accurate detection requires the loop coolant to be static. Thus, current accurate detection cannot be done online and requires offline methods, i.e., the loop coolant must be removed and taken to a laboratory for detection. However, the technical solution of this invention sets up a parallel bypass, i.e., a target loop, in the main loop. The loop coolant flows in both the main loop and the target loop. When detection is needed, the loop coolant in the target loop is stopped, while the main loop continues to flow. This ensures that the detected loop coolant is static, while also ensuring that there is always flowing loop coolant, thereby achieving accurate online monitoring of whether the fuel element cladding is damaged and reducing the radiation risk to personnel from offline sampling.

[0060] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention. Those skilled in the art will understand that the modules in the apparatus of the embodiment can be distributed within the apparatus of the embodiment as described, or they can be located in one or more apparatuses different from this embodiment, with corresponding changes. The modules of the above-described embodiment can be combined into one module, or further divided into multiple sub-modules. The serial numbers used above are for descriptive purposes only and do not represent the superiority or inferiority of the implementation scenarios. The above disclosures are merely a few specific implementation scenarios of the present invention; however, the present invention is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A reactor loop nuclide online monitoring system, characterized in that, The system includes: a sampling module, a control module, and a monitoring module; The sampling module includes a main circuit and a target circuit connected in parallel; The control module is used to control the flow of the loop coolant in the main circuit and the target circuit, so as to cut off the loop coolant in the target circuit as the loop coolant to be tested, while the loop coolant in the main circuit continues to flow; The monitoring module is used to monitor the activity of the target γ radionuclide in the coolant of the circuit under test.

2. The system according to claim 1, characterized in that, The monitoring module includes a shielding unit, a detection unit, a collimation unit, and a data processing unit; The shielding unit includes a shielding chamber, the shielding chamber includes a receiving cavity and a collimation hole communicating with the receiving cavity, the detection unit includes a detector, the detector is located in the receiving cavity, and the probe of the detector is opposite to the collimation hole, the collimation hole is used to be opposite to the target circuit, so that the probe receives γ-rays emitted by the coolant of the circuit under test in the target circuit; The shielding chamber also includes shielding components covering both sides of the collimation hole. The collimation unit is used to adjust the distance between the shielding components to adjust the collimation width of the collimation hole to the target collimation width. The detector is used to detect γ-rays in the coolant of the circuit under test that pass through the target circuit and the collimation hole in sequence and enter the probe, thereby obtaining a first energy spectrum signal. The data processing unit is used to determine the activity of the target γ-radionite in the coolant of the circuit to be tested based on the first energy spectrum signal, the known γ-radionite activity of the radioactive standard solution, and the target standard width.

3. The system according to claim 2, characterized in that, The sampling module includes one main circuit and N pipelines; The control module is also used to control one of the N pipelines to move to be opposite to the collimation hole, and to use the pipeline that moves to be opposite to the collimation hole as the target loop, wherein N is greater than or equal to 1, so as to detect loop coolant from different sources or loop coolant from the same source at different times.

4. The system according to claim 2, characterized in that, The sampling module further includes: the N+1th pipeline, which contains a radioactive standard solution; The control module is also used to control the N+1th pipeline to move to be opposite to the collimation hole; The collimation unit is also used to adjust the collimation width of the collimation aperture so that the intensity of the γ rays in the radioactive standard solution entering the detector through the N+1th pipeline and the collimation aperture in sequence meets the dead time requirement, thereby obtaining the target collimation width range. The collimation unit is also used to adjust the collimation width of the collimation hole to different target standard widths within the range of the target standard width; The detector is also used to detect γ rays in the radioactive standard solution that enter the probe sequentially through the N+1th pipeline and the collimation hole under different target standard widths, and to obtain a second energy spectrum signal corresponding to each target standard width; The data processing unit is further configured to calculate the efficiency value corresponding to the target standard width based on the known γ radionuclide activity of the radioactive standard solution, the second energy spectrum signal, and the target standard width corresponding to the second energy spectrum signal, and to determine the target γ radionuclide activity in the coolant of the circuit under test based on the first energy spectrum signal, the efficiency value corresponding to the target standard width, and the target standard width.

5. The system according to claim 4, characterized in that, The N+1 pipeline includes a test section and a non-test connection section. The test section is a rigid pipe so that the distance from each position of the coolant in the test circuit in the target circuit emitting gamma rays to the detector corresponds to the distance from each position of the radioactive standard solution in the N+1 pipeline emitting gamma rays to the detector. This makes the efficiency value corresponding to the target collimation width determined based on the known gamma radionuclide activity of the radioactive standard solution used to calculate the target gamma radionuclide activity in the coolant of the test circuit. The non-test connection section is a flexible pipe to enable the movement of the pipeline.

6. The system according to claim 5, characterized in that, The data processing unit is used to calculate the absolute activity by multiplying the first energy spectrum signal by the efficiency value corresponding to the target standard width, calculate the target cross-sectional area with the target standard width as the diameter, calculate the volume of the coolant in the test circuit by multiplying the target cross-sectional area by the length of the test segment, and calculate the ratio of the absolute activity to the volume to obtain the target γ radionuclide activity of the coolant in the test circuit.

7. The system according to claim 1, characterized in that, The system also includes: an alarm module; The alarm module is used to determine whether the casing is damaged based on the activity of the target gamma radionuclide. If it is damaged, an alarm signal is issued.

8. The system according to claim 2, characterized in that, The detection unit further includes a cooler, which is located in the receiving cavity and is used to adjust the operating temperature of the detector to a preset temperature range.

9. A method for online monitoring of nuclides in a reactor loop, characterized in that, The method includes: The control loop coolant flows in the main loop and the target loop to cut off the loop coolant in the target loop as the coolant for the loop under test, while the loop coolant in the main loop remains in flow, wherein the target loop and the main loop are connected in parallel; Monitor the activity of the target γ-radioactive nuclide in the coolant of the circuit under test.

10. The method according to claim 9, characterized in that, The monitoring of the activity of the target gamma radionuclide in the coolant of the circuit under test includes: Adjust the collimation width of the collimation hole to the target collimation width; The first energy spectrum signal is obtained by detecting the γ-rays in the coolant of the circuit under test that pass through the target circuit and the collimation hole in sequence and enter the probe. The activity of the target γ-radionium nuclide in the coolant of the circuit under test is determined based on the first energy spectrum signal, the known γ-radionium activity of the radioactive standard solution, and the target standard width.

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